Numerous methods and apparatus exist for treating biological tissue with electromagnetic radiation that is derived from a fluorescent light source. For example:
U.S. Pat. No. 6,981,970 discloses an epilation method using light produced by a fluorescent material pumped with ultraviolet light from an ultraviolet light source. In one embodiment, light passes along a path through a fluorescent block, and then though a filter to prevent unwanted wavelengths of light from reaching the skin. In other embodiments light passes along a first path to a fluorescent block, and then in a second perpendicular path to the skin.
U.S. Pat. No. 6,902,563 discloses an irradiation device for therapeutic treatment of skin. The device transforms the UV parts of the spectrum emitted by a light source using various kinds of foil (e.g., silicone elastomers or fluorpolymers, particularly PTFE (e.g., TEFLON®), doped with anorganic phosphors). Undesired portions of the emission spectrum can be removed using a filter.
U.S. Pat. No. 7,208,007 discloses a fluorescence concentrator system that provides for a high brightness light source. The system can include a host doped with fluorescent material, which is optically pumped by an adjacent illumination source. The fluorescence concentrator captures a portion of the isotropically emitted fluorescent light and guides it to an output surface. Light from the lamp that does not interact with the fluorescence concentrator passes through the concentrator and is not directed to the skin. Filters can be used to eliminate undesired wavelengths.
U.S. Pat. No. 5,320,618 discloses a device for the treatment of undesired superficial skin afflictions. The device includes a light source for producing light including a first predetermined wavelength, a light transforming means (e.g., fluorescent dye) for transforming the first predetermined wavelength to a second predetermined wavelength, and a guide means for directing the second predetermined wavelength to a predetermined location (e.g., tissue).
U.S. Pat. No. 7,252,628 discloses a device for treating human skin with radiation. A radiation filter is provided in the radiation path. The radiation filter includes water which is in solid state at least during an initial phase of operation of the device. The radiation filter can contact the skin and can include a fluorescent dye.
U.S. Pat. No. 7,083,610 discloses a device for irradiating tissue including a fluorescent element positioned to receive pump radiation having a narrow spectral band and responsively generate radiation by spontaneous emission, the fluorescent element delivering at least a portion of the diffuse emitted radiation toward a tissue target. The device also includes a substantially transparent window having a proximal face positioned adjacent to the fluorescent element and a distal face for contacting the target.
However, these methods and apparatuses produce wavelengths of light (e.g., from the light source, which travel unaltered to the biological tissue) that are harmful, non-therapeutic, or otherwise undesirable for treating biological tissue. Therefore, these methods and apparatuses are complicated and hindered by means for preventing these undesirable wavelengths from reaching the biological tissue. For example, these methods and apparatuses can require a filter between the fluorescent material and the biological tissue to prevent undesirable wavelengths from reaching the biological tissue. Further, these methods and apparatus can require an arrangement where light travels substantially along two perpendicular axes, one from the light source to the fluorescent body and another from the fluorescent body to the biological tissue.